Moves Bytecode::IsBytecodeEqual from objects.cc to code.cc.

Bug: v8:9183
Change-Id: I1f6ff1cc388c5f22de951bc75514dd08c25e500a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1667420
Auto-Submit: Dan Elphick <delphick@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62307}